The maintenance of a negative pressure or suction in a prosthetic socket or at a related interface to thereby facilitate a desired limb suspension is typically achieved through the use of an expulsion-type check valve (e.g. auto, manual or both). Such valves are typically configured to provide a threaded base or seat. The base, in turn, normally supports a threaded valve insert that is configured to ensure a proper airtight seal.
Proper placement of the valve insert relative to the base requires a high degree of dexterity and hand-eye coordination, especially when used in a prosthetic limb. That is, most typically the valve base is located at the most distal aspect of a limb socket. The base is typically thermoformed or laminated into the socket. Such a location can be difficult to see, but can also present an awkward relative alignment angle to mount or detach the valve insert.
Because the valve threads, which exhibit a relatively fine pitch, have to line up perfectly in order for the valve insert to be set properly, the combination of poor visibility and high demands for physical dexterity typically result in difficult donning situations for individuals with sound hands and fingers. Removal of the valve can present similar challenges, as the quality of the seal is often related to how tight the insert has been screwed into the valve base. A significant amount of friction can result from overzealous tightening of the valve insert, making it extremely difficult to remove.
For individuals with an involved upper extremity or extremities (e.g. injured, deformed, diseased or the result of insufficient congenital development), the insertion and/or removal of the valve insert from the valve seat can prove impossible. This circumstance is particularly onerous for the debilitated user who has to periodically self-adjust the limb.
The foregoing difficulties have been overcome with the present valve assembly, which in one construction provides a threadless base that is adapted to receive a mating, latched insert. The valve assembly at the coupling junction between the base and insert is particularly constructed to provide for a latched connection. The interconnection provides a sliding, sealed valve insert piece that is respectively pushed or pulled from the seat or base during mounting and removal. The connection is maintained or broken with cooperating latch arms that assure proper insert retention.
In another construction, a threadless base supports an insert via O'rings and a magnetic coupling. A spring biased valve piece or stem piece having adjustable air pressure release capabilities is concentrically supported in the insert.